1. Field of the Invention
The present invention relates in general to the field of electronics, and more specifically to a method and system for consolidation of lamp power conversion and external communication control using current modulated by an input switching stage of the lamp.
2. Description of the Related Art
Lighting systems continue to advance. For example, protocols and specialized communication hardware have been developed and placed within lamps to allow communication between lamps and a central communication system. The communication systems facilitate monitoring, controlling, informing, and automating the delivery and use of energy.
FIG. 1 depicts a lighting system 100 that includes lamps 102.1-102.N that each includes a respective, dedicated communication controller 104.1-104.N. “N” is an index integer representing a total number of lamps. The lighting system 100 receives an AC supply voltage VIN from voltage supply 106. The supply voltage VIN is, for example, a nominally 60 Hz/110 V line voltage in the United States of America or a nominally 50 Hz/220 V line voltage in Europe and the People's Republic of China. The lighting system also includes a central communication processor 108. The communication controllers 104.1-104.N exchange data with the central communication processor 108 to facilitate monitoring, controlling, informing, and automating the delivery and use of energy by the lamps 102.1-102.N.
FIG. 2 represents an exemplary supply voltage VIN waveform 202 and input current iIN waveform 204. Referring to FIGS. 1 and 2, the communication controllers 104.1-104.N are dedicated controllers for exchanging data with the central communication processor 108. The communication controllers 104.1-104.N exchange data with the central communication processor 108 in accordance with a specific data transfer protocol such as ZigBee or X10. “X10” is an international, open industry standard for communication among electronic devices used for home automation. Using the X10 protocol, data is transmitted within 200 μsecs of the zero crossings, such as zero crossings 206 and 208, of the supply voltage VIN. In at least one embodiment, an X10-based communication controller 106 transmits data representing a logical one using 1 msec, 120 kHz digital data transmission pulses 206 and 208. Logical zeros are indicated by the lack of a pulse at zero crossing of the supply voltage VIN. The data pulses are transmitted to the central communication processor 108 via power lines 110 and 112. ZigBee-based communication controllers 104.1-104.N exchange data with the central communication processor 108 using wireless transceivers (not shown). In another embodiment, the lamps 102.1-102.N exchange data with the central communication processor 106 via optional serial data lines 113.1-113.N.
Lamps 102.1-102.N also include respective power controllers 114.1-114.N. The communication controllers 104.1 and 104.N provide data to the power controllers 114.1-114.N that indicates various power settings, and the power controllers 114.1-114.N control power within the lamps 102.1-102.N. For example, when the central communication processor 108 generates command data to turn light sources 116.1-116.N ON, the communication controllers 104.1-104.N receive and decode the command data and notify the respective power controllers 114.1-114.N to turn the light sources 116.1-116.N ON.
FIG. 3 depicts a lamp 300, which represents one embodiment of each of the lamps 102.1-102.N. The lamp 300 includes a light source 302, such as an incandescent light bulb. The communication controller 304 transmits and receives data from the central communication processor 108 (FIG. 1) either through the power lines 110 and 112 or via antenna 306. If the central communication processor 108 issues a power related command, the communication controller 304 passes the command to the power controller 308. The power controller 308 then complies with the command by, for example, operating switch 310 to terminate and restore power to light source 302, thus, respectively turning light source 302 ON and OFF. Additionally, lamp 300 includes a sensor 310 that can provide sensed data, such as temperature data, to communication controller 304. The communication controller 304 then transmits the sensed data to the central communication processor 108.
Thus, lighting systems are able to communicate with a central communication controller. However, the lighting systems utilize a separate, dedicated communication controller to provide communications with the central communication controller.